1. Field
The following description relates to lamp assemblies. Embodiments of the following description may be used in a ground illumination lamp for an exterior rear view mirror of a vehicle.
2. Description of Related Art
Lamp assemblies are being increasingly used in vehicle side mirrors (exterior rear view mirror assemblies) as value added features required by automotive manufacturers. Light emitting diodes (LEDs) or other similar point light sources are also being used more frequently as the light source in these lamp assemblies due to their efficiency and compact design.
An LED light source is inherently directional (with an approximate Lambertian distribution) meaning that the relative luminous intensity of the LED varies away from the optical axis of the LED. The luminous intensity is highest at 0° (along the optical axis) and drops off significantly as the viewing angle increases. When an LED is viewed directly (i.e. along the optical axis) the light source can appear very bright. As the power of the LED increases, the brightness can increase to a level whereby an uncomfortable glare is experienced by a person viewing the LED directly.
In some lamp assemblies, a high level of brightness is required. For example, a ground illumination lamp or spotlight integrated into a vehicle side mirror is required to illuminate an area of ground adjacent a vehicle. For the ground illumination lamp to be effective, a light source of high luminous intensity is needed. In the past, lamp assemblies that have been used to provide ground illumination have achieved the required level of brightness but in the process created too much unwanted glare. To reduce the glare, a lower power light source would have to be used which compromises the ability of the lamp assembly to appropriately illuminate the ground area.
The present invention seeks to provide an improved lamp assembly that overcomes some of the above mentioned difficulties or at least provides the public with a useful choice. Other advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, a preferred embodiment of the present invention is disclosed.